The present invention generally relates to semiconductor device fabrication methods and their resulting structures. More specifically, embodiments of the present invention relate to fabrication methods and resulting structures for changing performance characteristics of a field-effect transistor, such as, for example, a fin field-effect transistor (finFET).
With contemporary semiconductor device fabrication processes, a large number of semiconductor transistor devices, such as finFETs, can be fabricated in and on at least one wafer. In contrast to planar metal oxide semiconductor field effect transistors (MOSFETs), in a finFET device, a source, drain and channel are built as a three-dimensional fin in or on a semiconductor substrate. The fin serves as the main body of the device. The gate electrode is wrapped over the top and sides of the fin, and the portion of the fin that is under the gate electrode functions as the channel. The source and drain regions are the portions of the fin on either side of the channel that are not under the gate electrode. FinFETs can be built on silicon-n-insulator (SOI) substrates.